#include<stdio.h>

int ldc()
{
	int a = 1;
	int b = 2;
	int c = 3;
	int n = 0;
	int i = 4;
	
	if (n < 3)
	{
		return a;
	}
	else
	{
		if (n == 3)
		{
			return b;
		}
		else {
			while (i < n) {
				i=i++;
				a = b;
				c = b + c;
				b = c - b;
			}
			return c;
		}
	}
}
int main()
{
	int x;
	int f;
	int h;
	int j;
	int y;
	scanf_s("d%\n",&x);
	y = ldc(x,f,y,h,j);
	printf("d%", y);

}
	